This isn't likely a problem with Downcast. HomePod is treated just like any other AirPlay device or external audio route. There haven't been any similar reports of AirPlay troubles with other devices, so this feels like a HomePod issue or the combination of HomePod and certain WiFi networks.
Should be fixed or significantly improved in v2.9.30
Issues manually reordering playlists.
This seems to mostly be an issue while feeds are being refreshed. For now, please try to avoid doing this in the middle of a feed refresh.
Should be resolved in v2.9.30
Background crashing issues - Fixed in beta
Now playing information may stop updating - Fixed in beta
HTTP response caching issue - Fixed in beta
"Delete All" not working correctonly iPad - Fixed in beta
Display of total time for playlists that only include played episodes not showing up - Fixed in beta
Badge count may become out of sync - Fixed in beta
Occasional layout issue on playlists - Fixed in beta
Long press menu for episodes doesn't work for some episode rows - Fixed in beta
iPhone X - Not autohiding home bar during videos
Playlist Episode Layout - Most users like the extra detail. If you don't, a new feature is on the way that will let you select from a few different levels of detail. Beta in a few days.
Layout issues on iPhone X
'Queued for download' label misaligned on playlists & downloads list
Group row on podcasts list doesn't stretch to fill screen in landscape
Some variable bitrate episodes terminate early
iCloud Syncing - Cannot enable iCloud Syncing options under certain conditions.
Fixed in v2.9.18 (Waiting for review)
General UI sluggishness - Mostly affects old devices
Solution in the next major update (3.x)
iOS 10 Beta 2 issues
Frequent crashes - Appears to be an iOS bug, hoping this will be resolved by the next iOS beta.
Pausing while connected to Bluetooth devices on iOS 10 beta 2 - Appears to be an iOS bug, hoping this will be resolved by the next iOS beta.
Table row section header indentation is missing
Fixed in next release (2.9.16)
Can't download/stream directly from search results
Workaround - Subscribe to the podcast first, then you'll be able to download or stream individual episodes.